Physical Quantities & Units
Definitions: Physical Quantities & Units
- One exam question, the mark-scheme answer, and the exact phrases that score (highlighted, then listed below in the same colour).
Exam question
State what is meant by a scalar quantity and by a vector quantity.
Model answer
A scalar has magnitude only. A vector has magnitude and direction.
Marking points
1 mark each- 1magnitude only(1)
- 2magnitude and direction(1)
Exam question
State what is meant by a systematic error and by a random error.
Model answer
A systematic error shifts every reading by the same amount in the same direction. A random error scatters readings on both sides of the true value by changing amounts.
Marking points
1 mark each- 1every reading by the same amount in the same direction(1)
- 2scatters readings on both sides of the true value by changing amounts(1)
Exam question
State what is meant by the precision of a measurement.
Model answer
Precision means the readings close to each other.
Marking points
1 mark each- 1readings close to each other(1)
Exam question
State what is meant by the accuracy of a measurement.
Model answer
Accuracy means the readings are close to the true value.
Marking points
1 mark each- 1close to the true value(1)
Exam question
State what is meant by the uncertainty in a measurement.
Model answer
The uncertainty is the range around the value within which the true value is expected to lie.
Marking points
1 mark each- 1the range around the value within which the true value is expected to lie(1)